There is technology available for automatically detecting an abnormal state in a room occupant, particularly a person who requires care, such as an elderly person. For instance, the fall detector in Japanese Unexamined Patent Application Publication No. 2000-285223 (Patent Document 1) is provided with a sidewall camera that captures an image of the room's occupant from the side, and a ceiling camera that captures an image of the room's occupant from above. An image processing unit uses the images captured by the cameras to calculate the distance from the occupant to the sidewall camera, as well as to calculate the occupant's height. A height correction unit makes corrections to the height calculated taking into account the error generated due to the difference in the distance from the occupant to the sidewall camera. A determination unit detects the occupant's falling motion on the basis of changes per unit time in the occupant's height information obtained from correcting the occupant's height.